There has been continuing research effort to develop resin systems which are adapted to be cast into supported or self-supported films having flame, solvent and mildew-resisting properties, and more particularly, moisture barrier properties. Many of the developed resin systems characteristically contain a high content of halogen atoms to impart the moisture barrier and other desirable properties inherent in the systems.
U.S. Pat. No. 2,129,370 describes a sheet article suitable for wrapping purposes, characterized by being heat sealing, transparent and highly resistant to moisture vapor. The article consists of a regenerated cellulose sheet having a coating thereon composed essentially of a rubber hydrochloride and one or more substances selected from paraffin wax, chlorinated diphenyl, polycoumarone, rosin and dammar.
U.S. Pat. No. 2,194,690 describes a coating and impregnating composition for cellulosic materials comprising chlorinated paraffin, chlorinated rubber, tricresyl phosphate, pigment, filler, zinc borate and volatile solvent.
U.S. Pat. No. 2,252,485 describes a coating composition which consists of chlorinated high molecular weight iso-olefin polymer and chlorinated paraffin dissolved in a volatile organic solvent.
U.S. Pat. No. 2,301,959 describes the preparation of moistureproof wrapping paper by the coating of a base formed of nonfibrous base sheet with a composition containing halogenated rubber, wax and dimethylol urea ether resin dissolved in an organic solvent. In Example 1 of U.S. Pat. No. 2,384,132 there is illustrated the preparation of a furniture lacquer for spray application consisting of chlorinated rubber, polyvinyl acetate and chlorinated paraffin dissolved in a toluene/butyl acetate solvent blend.
In Example 2 of U.S. Pat. No. 2,388,326, regenerated cellulose film is coated with a formulation consisting of 1,2-dihydronaphthalene polymer, chlorinated rubber, paraffin wax, chlorinated paraffin wax and calcium salt of hydrogenated rosin dissolved in toluene.
U.S. Pat. No. 2,490,536 describes a composition for rendering paper, regenerated cellulose and the like moistureproof and heat sealing, which composition comprises chlorinated rubber, ethylenevinyl acetate copolymer and paraffin wax dissolved in an organic solvent such as toluene.
U.S. Pat. No. 3,200,093 describes a composition for coating milk cartons and frozen food wraps which consists of a blend of paraffin wax and chlorinated polyethylene. The composition is applied in molten form to the substrates.
U.S. Pat. No. 3,944,717 describes a coating system for a telephone surface cable which has water-resisting capability. The coating system comprises an admixture of polyvinyl chloride, chlorinated polyethylene and chlorinated paraffin, which is applied at a temperature of 220.degree.-300.degree. F.
As it is apparent, the prior art methods for providing substrates with moisture resistant and flame resistant surfaces generally involve coating the substrates with a halogen-containing composition dissolved in an organic solvent. In some cases, a non-volatile halogen-containing resin composition is applied to the respective substrates in a molten state. There remains a need for moisture barrier coating compositions which can be applied as protective film on substrate surfaces without the presence of a volatile solvent or the need for elevated temperatures to effect curing of polymerizable components of the coating composition.
Accordingly, it is a main object of this invention to provide a room temperature curable resin composition exhibiting properties adapted for protecting substrate surfaces with a moisture barrier coating film.
It is another object of this invention to provide a low viscosity curable coating system containing halocarbon components which contribute moisture-resistant properties to the coating system.
It is a further object of this invention to provide a curable halogen-containing coating composition which cures rapidly at ambient temperatures as a 100% solids system under the influence of ultraviolet radiation.
Other objects and advantages of this invention shall become apparent from the accompanying description and examples.